Attorney General Jeff Sessions proposed putting National Security Council staffers through a lie detector test to identify those leaking information to the media, several outlets reported late Sunday.

Axios reported that as recently as last month, Sessions proposed “a one-time, one-issue, polygraph test” of every NSC staff member regarding leaked transcripts of President Donald Trump’s phone calls with foreign heads of state.

CNN reported, citing an unnamed source familiar with Sessions’ thinking, that the attorney general wanted to focus on finding out who leaked full transcripts of Trump’s phone calls with Mexican President Enrique Peña Nieto and Australian Prime Minister Malcolm Turnbull, which the Washington Post published in full in August.

Sessions was interested in those leaks, according to CNN, because of the limited number of people who had access to the transcripts.

A day after the Washington Post published transcripts of Trump’s calls with Peña Nieto and Turnbull, Sessions announced a crackdown on intelligence leaks and said he would review “policies affecting media subpoenas,” suggesting that the Department of Justice might pursue journalists in court in order to reveal their sources.